1. For the pH 4.5 buffer, you must use acetic acid and sodium hydroxide: СНЗСООН + NaОН — NaCH3CO0 + H20 The Ka of acetic acid is 1.8 x 10-5. Using the Henderson-Hasselbalch equation, calculate the molar ratio of [conjugate base]/[weak acid] that must be used in preparing the buffer. A. 0.29 В. 0.57 C. 0.87 D. 1.14
1. For the pH 4.5 buffer, you must use acetic acid and sodium hydroxide: СНЗСООН + NaОН — NaCH3CO0 + H20 The Ka of acetic acid is 1.8 x 10-5. Using the Henderson-Hasselbalch equation, calculate the molar ratio of [conjugate base]/[weak acid] that must be used in preparing the buffer. A. 0.29 В. 0.57 C. 0.87 D. 1.14
Chemistry
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ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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![A generic version for Drug X is applying registration to the FDA. For the generic drug to be approved,
it must prove bioequivalence with an innovator/originator drug. However, the company registering
Drug X is applying for an exemption for in vivo bioequivalence testing. To qualify for this exemption,
one of the requirements is to prove that it can be highly soluble in an aqueous buffer of pH 1.2, 4.5, 6.8.
As the drug formulator, you need to prepare these buffers to test your sample.
1. For the pH 4.5 buffer, you must use acetic acid and sodium hydroxide:
СНЗСООН + NaOH — NaCНЗСОО + Н20
The Ka of acetic acid is 1.8 x 10-5. Using the Henderson-Hasselbalch equation, calculate the molar
ratio of [conjugate base]/[weak acid] that must be used in preparing the buffer.
А. 0.29
В. 0.57
С. 0.87
D. 1.14
2. The only remaining NaOH in the lab is 100 mL of 1.0 M NaOH solution. Given this amount, how
many moles of acetic acid must be used to prepare 1 L of the buffer.
A. 0.088 mol
B. 0.175 mol
C. 0.275 mol
D. 0.350 mol
3. If the lab has an available stock of 5.0 M acetic acid solution, how many mL of this solution must be
used to obtain the calculated moles of acetic acid?
A. 17.6 mL B. 35.0 mL
C. 55.0 mL
D. 70.0 mL
4. Using the Van Slyke equation, calculate the buffer capacity, B, of the buffer to be prepared.
A. 0.100
B. 0.146 C. 0.200 D. 0.235
5. The Ka of NaH2PO4 6.2 x 10-8. Using the Henderson-Hasselbalch equation, calculate the molar
ratio of [conjugate base]/[weak acid] that must be used in preparing the buffer.
Α. 0.39
В. О.78
С. 1.56
D. 2.34
6. There is an available 50 mL of 0.2M NaH2PO4 in the laboratory. Convert this first to the moles of
NaH2PO4. The molar mass of NaH2PO4 is 119.98 g/mol.
A. 0.005 mol
B. 0.010 mol
C. 0.025 mol
D. 0.045 mol
7. Given the number of moles of NaH2PO4 available as computed above and the molar ratio calculated,
which of the following moles of NaOH when added to NaH2PO4 will produce the required buffer
A. 0.0061 mol
B. 0.0078 mol
C. 0.0156 mol
D. 0.0390 mol
8. If a readily available 0.2 M NaOH is present in the lab, how many mL of this solution will you use to
supply the calculated moles from above?
А. 30.5 mL B. 39.0 mL
C. 78.0 mL
D. 195.0 mL](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F05dfd1b6-08d3-41c2-80bd-de7c0f166124%2F92c37135-7c72-48e0-82df-b34d2208bdee%2F5p9c6k_processed.jpeg&w=3840&q=75)
Transcribed Image Text:A generic version for Drug X is applying registration to the FDA. For the generic drug to be approved,
it must prove bioequivalence with an innovator/originator drug. However, the company registering
Drug X is applying for an exemption for in vivo bioequivalence testing. To qualify for this exemption,
one of the requirements is to prove that it can be highly soluble in an aqueous buffer of pH 1.2, 4.5, 6.8.
As the drug formulator, you need to prepare these buffers to test your sample.
1. For the pH 4.5 buffer, you must use acetic acid and sodium hydroxide:
СНЗСООН + NaOH — NaCНЗСОО + Н20
The Ka of acetic acid is 1.8 x 10-5. Using the Henderson-Hasselbalch equation, calculate the molar
ratio of [conjugate base]/[weak acid] that must be used in preparing the buffer.
А. 0.29
В. 0.57
С. 0.87
D. 1.14
2. The only remaining NaOH in the lab is 100 mL of 1.0 M NaOH solution. Given this amount, how
many moles of acetic acid must be used to prepare 1 L of the buffer.
A. 0.088 mol
B. 0.175 mol
C. 0.275 mol
D. 0.350 mol
3. If the lab has an available stock of 5.0 M acetic acid solution, how many mL of this solution must be
used to obtain the calculated moles of acetic acid?
A. 17.6 mL B. 35.0 mL
C. 55.0 mL
D. 70.0 mL
4. Using the Van Slyke equation, calculate the buffer capacity, B, of the buffer to be prepared.
A. 0.100
B. 0.146 C. 0.200 D. 0.235
5. The Ka of NaH2PO4 6.2 x 10-8. Using the Henderson-Hasselbalch equation, calculate the molar
ratio of [conjugate base]/[weak acid] that must be used in preparing the buffer.
Α. 0.39
В. О.78
С. 1.56
D. 2.34
6. There is an available 50 mL of 0.2M NaH2PO4 in the laboratory. Convert this first to the moles of
NaH2PO4. The molar mass of NaH2PO4 is 119.98 g/mol.
A. 0.005 mol
B. 0.010 mol
C. 0.025 mol
D. 0.045 mol
7. Given the number of moles of NaH2PO4 available as computed above and the molar ratio calculated,
which of the following moles of NaOH when added to NaH2PO4 will produce the required buffer
A. 0.0061 mol
B. 0.0078 mol
C. 0.0156 mol
D. 0.0390 mol
8. If a readily available 0.2 M NaOH is present in the lab, how many mL of this solution will you use to
supply the calculated moles from above?
А. 30.5 mL B. 39.0 mL
C. 78.0 mL
D. 195.0 mL
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